Those Bosses You Can Never Kill

Almost in every game, there is a final boss for you to kill. Killing boss is really splendid, but what if you met a boss that could never be killed? No matter how hard you tried to destroy him, he appeared after a period and laughed "I'm resurrected". And then you could do nothing but to fight with him again and again…Today let's talk about those bosses who can never be killed. How many of them did you ever try to kill?